Connecter for edgewise-wound resistance coils



Sept. 10, 1929. G. H. WHITTINGHAM 1,728,090

CONNECTER FOR EDGEWISE' WOUND RESISTANCE COILS Filed May 29 .1926

Patented Sept. 10, 1929.

UNITED STATES PATENT OFFICE.

GEORGE wHITTING-HAM, OF BALTIMORE, MARYLAND, ASSIGNOR TO MONITOR.

CONTROLLER COMPANY, OF BALTIMORE, MARYLAND, A CORPORATION 01' MARY- LAND.

CONNECTER FOR EDGEwISE-WOUND RESISTANCE COILB.

Application filed Kay 2a, 1926. Serial in. 112,504.

This invention relates to connecters adapted for connecting wires to resistance units composed of ribbons of resistance metal wound on edge and mounted on supporting members, having coverings of refractory material, such as porcelain. Terminals for the coils cannot be satisfactorily secured to the refractory material because of its hard and brittle nature, and the ends of the coils are diflicult to bend or twist into suitable form for attachment to the terminals. Where it is desired to take off taps or leads from intermediate parts of the coils, connectersare difficult to apply because they cannot be secured to the refractory materia The connecter of the present invention is adapted to be mounted upon the coil itself and is so constructed that it can be readily applied to or taken ofl' of any part of the 2 coil. The connecter comprises a sheet metal plate having a central part suitably formed to constitute a binding post, and having arms diverging from the lower part of the post and provided with U-shaped portions ada ted to 2 extend over the outer edges of two a jacent convolutions of the coil. The central parts of these U-shaped portions areprovided with openings to receive clamping screws. Glamping screws are provided, having oblong heads which may be inserted through the space between adjacent convolutionsand then turned crosswise, and when these screws are tightened, they engage the inner ed es of said convolutions and draw the centra parts of the U-shaped portions firmly against the outer edges of the convolutions, Thus, the connecter becomes rigidly secured to the ed ewise wound coil and is firmly supported y it. The resistance unit shown in the cp'resent application comprises a metal supportlng bar 7 having a covering composed of refractory material, the latter having toothed ridges onto which the coil is threaded, and the connecter is formed with a notch which may be made to straddle one of these ridges to osition the connecter and help to keep it rom slipping around on the coi In the accompanying drawing,

Fig. 1 is a side elevation of the resistance unit, partly broken away, showing several volutions and draw the of the connecters secured to the edgewise wound coil;

Fig. 2 is a section on the line 2-2 of Fig. 1;

Fig. 3 is a top plan view of one of the connecters, the clam ing screws being omitted;

gig. 4 is a sim ar view of a modification; an

Fig. 5 is a section on the line 5 -5 of Fig. 2, the insulating support for the coil being removed.

Referring to the drawing, a indicates a resistance unit, comprising a metal supporting bar 1, an insulating covering 2, of refractory material, such as porcelain, and a coil 3, consisting of a ribbon of resistance metal wound on edge and-mounted on the insulating covering. The supporting bar and the insulating covering are relatively flat, and the latter has on its op osite edges teeth 2", which space the convo utions ofthe coil apart.

In Fig. 1, three connectors, b, b and b, are shown, these connectors being all alike. Each connecter comprises a metal plate 4, having a part 5 suitably shaped to form a bindin post and having arms 6, which diverge rom the lower end of the post and in the plane of the latter. Each arm has a U-shaped portion 7 at its end, ada ted'to fit over two adjacent convolutions o the coil. Each U-shaped portion is formed'by providing a tongue on the arm'which has a part 8 bent over at ri ht angles to the arm, and a part 9, which is bent downwardly at right angles to the part 8. Thus, the arm and-the parts '8 and 9 form a U-shaped' structure adapted to fit overltwo of the convolutions of the coil. The central part 8 of each U-shaped portion has an opening 8', adapted to receive a clamping screw 10. Each clamping screw has an oblong head 10, which may be passed throu h the coil between adjacent convolu- Qtions', at which, when turned crosswise, will engage the inner edges of the convolutions, as shown in Figs. 1 an '2. Nuts 11 are provided on theclamping screws, and when the latter are tightened, the heads on the clamping screws bear against the inner edges of the coharts 8- of the U-shaped portions against t e outer edges of 100 the convolutions. Thus, when the screws are tightened, the connecter is rigidly secured to the coil and is supported thereby independently of the insulated support. The connecter shown in the drawing is provided with a notch 12, at the base of the binding post,

adapted to straddle the toothed ridges of the insulator, for ositioning the connecter on the coil, and t is interlocking engagement cause if a clamping screw, with an oblong head, becomes lost, as an ordinary screw having a head slightly wider than the space between adjacent convolutions of the coil may be forced through the convolutions at a point removed from the connecter, where the coils have room to spread, and the screw may then be brought up to the connecter and its shank slid into the slot and tightened.

It will be evident that connecters such as described may be applied to any part of the coil after the latter is on the insulator, and

that the connecters can be readily removed when desired.

What I claim is:

1. A connecter for edgewise wound resistance coils comprising a sheet metal plate having a central portion, constituting a binding post, and arms diverging from the lower part of said post, each portion adapted to fit over the edges of two adjacent convolutions of a coil, and clamping screws extending through said portions and arm having a U-sha'ped.

volutions and adapted to bear against the inner edges of said convolutions.

4. A connecter for resistance units of the type comprising an insulator having toothed ridges, and an edgewise wound coil threaded on to the insulator said connecter comprising a sheet metal ate having a central porthe base of the bindin post adapted to straddle the insulator, an arms divergin from the lower part of said post, each arm aving a U-shaped portion adapted to fit over the edges 0 two adjacent convolutions of the coil, and clamping screws extendin through said portions and having heads adapted to bearagainstthe inner edges of saidconvolutions.

In testimony whereof I hereunto afiix my signature.

GEORGE H. WHITTINGHAM.

tion, constituting a binding post, a notch at havin heads adapted to bear against the inner e ges of said convolutions.

2. A connecter for edgewise wound resistance coils comprising a sheet metal plate having a central portion, constituting a binding post, and arms diverging from the lower part I of said post, each arm having a portion adapted to fit over the edges of two adjacent convolutions of a coil, and clamping screws extending through said portions a d having heads insertable through the space between said convolutions and adapted to bear against the inner edges of said convolutions.

3. A connecter for edgewise wound resistance coils comprising a sheet metal plate having a central portion, constituting a binding post, and arms diverging from the lower part of said post, each arm having a U-shaped portion adapted to fit over the edges of two adjacent convolutions of a coil, said portion having a notch in its central part extending parallel with the plate, and clamping screws aving shanks adapted to fit in the notch and having heads insertable between said con 

